Chelsea concerned over Diego Costa's situation

Premier League champions Chelsea are reportedly concerned by Diego Costa's increase in weight while holidaying in his native Brazil.

The Spain international has been training alone in the South American nation over the past two months, and the Blues feel that the player has put on extra weight through his social updates, Sport reveals.

Costa has repeatedly stated his desire to return to Atletico Madrid despite the ongoing transfer ban which restricts them from registering him until the New Year.

Atletico Madrid were initially hoping to seal a bargain deal for their former marksman, but the Blues' reluctance to sell on the cheap has broken down negotiations.

As a result, the Blues believe that they could be stuck with the 28-year-old, who could be fined as much as £300,000 for not reporting to first-team training.

Costa has previously admitted that he will have to play regular football somewhere in order to remain within national team reckoning, and a temporary switch to AC Milan could yet be an option this summer.